PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 Life expectancy: At least 12 weeks Hematopoietic: Absolute granulocyte count at least 1,500/mm3 Platelet count at least 100,000/mm3 Hepatic: Bilirubin no greater than upper limit of normal (ULN) AST/ALT no greater than 2.5 times ULN Renal: Creatinine no greater than 1.5 times ULN Other: No other prior malignancy within the past 5 years unless definitively treated with no evidence of recurrence No known hypersensitivity to systemic liposomal formulations or drugs chemically related to study drug No other serious illness or medical condition that would preclude study No active uncontrolled infection No complete bowel obstruction No history of significant neurologic or psychiatric disorder that would preclude informed consent Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception